Current flexible sign face substrates are made with plasticized-pigmented vinyl. Embedded into this vinyl or sandwiched between several layers of the vinyl is a woven polyester scrim that gives the vinyl construction dimensional stability, that is, the vinyl construction tends not creep at elevated temperatures when the construction is put under tension. The polyester woven scrim also provides the sign face substrate with high tear resistance and tensile strength. Unfortunately, the polyester woven scrim used in commercially available sign face substrate is optically visible. For many applications such visibility is considered a defect.
Polyester woven scrim construction may also introduce other defects during the weaving process and final construction of the woven scrim, such as extraneous threads introduced from winding and unwinding the woven scrim during manufacturing. Loose threads can become embedded in the woven scrim and end up offering additional defects, over the original woven scrim, when backlit. Further, woven scrim is susceptible to wicking, which can lead to growth of mold and mildew.
Other sign face constructions useful for backlit and channel cut applications are made from rigid acrylics. Advantageously, sign face constructions prepared from the rigid acrylics can be self supporting, that is, an acrylic sign face can be slid into a frame, and the sign will not sag or appear otherwise unsightly and the rigid acrylics are generally optically uniform. Disadvantageously, the rigid acrylic is subject to cracking, shattering, and crazing. Furthermore, the rigid acrylics are costly to prepare and replace, and depending on the particular application can require labor-intensive installation.
U.S. Pat. No. 4,544,586 describes a laminar PET substrate laminated to a front light reflective layer useful as road sign markers and the like.
U.S. Pat. No. 4,680,234 describes a flexible weather-resistant film layer of a blend of a vinyl chloride polymer and chlorinated polyethylene and a second layer comprising a normally solid thermoplastic adhesive. The weather-resistant, multilayer film is used for architectural applications.
U.S. Pat. No. 4,693,926 describes a flexible decorative laminate useful as wall coverings on bulkhead panels in commercial aircraft. The laminate is lightweight, flexible, fire resistant, and decorative employing aluminum foil sheets.
U.S. Pat. No. 4,724,186 describes a flexible, weather resistant multilayer laminate film useful for a weatherable surface coating by lamination to a substrate having a weatherable layer. The coated substrates may be used in facia and other architectural film. The weatherable film is particularly suitable for use as a coating to a metal substrate.
U.S. Pat. No. 4,774,146 describes a coextruded thermoplastic for use as flexible packages.